Method and apparatus for adapting dentures



1964 c. P. VAN COURT ETAL 3,161,956

METHOD AND APPARATUS FOR ADAPTING DENTURES Filed May 2, 1960 R m m M N EW 2 m 0 W Lm R A 6 AA H I Y B Wf/ QO ATTORNEY5 United States Patent3,151,956 NETHQD AND APPARATUS FUR ADAPTlNG BENTURES Carl P. Van Court,Canoga Park, and Harold E. Kinsman,

Southgate, Caliii, assignors to Air-Balance Corporation,

a corporation of California Filed May 2, 1969, Ser. No. 26,109 3 Claims.(Cl. 32-19) This invention relates to the fabrication of artificialdentures and more particularly to an improved method and apparatus forestablishing angular mandibular-maxillary relationships to the end thatsuperior adaptability and comfort of finished dentures may be achieved.

This invention constitutes an improvement over the method and apparatusfor adapting dentures set forth in our United States Patent Number2,773,308, issued December 11, 1956. In this latter-mentioned patent,the extreme importance of having functional stresses and occlusalpressures between the mandibular and maxillary dentures equalized andmaintained is set forth. Unequal and incorrect pressures not only resultin shifting of the completed denture bases on the alveolar ridgesproducing occlusal disharmonies, soreness, and possibly much pain, butcan cause the more serious result of bone dystrophies; that is, theosseous foundations change and eventually tend to render the originaldentures out of harmony.

All or" the various objects and advantages of our prior United StatesPatent 2,773,308 are achieved by the improved method and apparatus ofthis invention, and the subject matter of said patent is accordinglyhereby incorporated in this application by reference.

in the method set forth in our prior United States patent, properangular relationship between the mandibular and maxillary trays or biteblocks in a lateral direction as well as in an anterior-posteriordirection is achieved by employing a flexible iluid chamber disposedbetween the opposing bite rims of the trays and inflated to a pressuresubstantially equal to the physiologic pressure corresponding to thediastolic cardiovascular pressure characteristic of the patient. Thisparticular presstu'e is determined by measuring the actual fluidpressure in the chamber after instructing the patient to close his mouthsufficiently to cause an anterior pin structure on the maxillary tray totouch lightly a cooperating plate secured to the mandibular tray.

With the pressure recorded, it is then possible to subsequently hold themandibular and maxillary bite blocks in a proper angular relationshipwhile applying quick setting material to distal support plates securedto the ends of the mandibular block. Hardening of this material whileholding proper pressure in the chamber thus fixes the mandibular andmaxillary blocks in proper relationship to each other notwithstandingpossible tiring of the patients muscles resulting in loss of muscletonus which would normally chan e the desired relationship. In otherwords, the fluid chamber itself serves as a substitute for the naturalphysiologic pressure of the particular patient so that extremelyaccurate relationships between the opposing blocks can be achieved.

While this prior method will enable the fabrication of properly fittingdentures, its success is dependent to a large extent on the proficiencyof the particular dentist in carrying out the method steps.

With the above in mind, it is a general object of tie present inventionto provide an improved method and apparatus for adapting artificialdentures involving fewer steps than have heretofore been deemednecessary and yet providing accurate mandibular-maxillary relationshipsto enable the fabrication of dentures of equal or even superior qualityto those provided by prior methods.

More particularly, it is an object to provide an improved method andapparatus for establishing lateral and anterior-posterior angularmandibular-maxillary relationships in cooperation with a conventionalcentric anteriorposterior and vertical indexing pin to the end thatdentures may be created in which the physiological forces are related tothe vascular pressures and the sensory nerve endings of the alveolarridges of the patient to establish maximum comfort for the patient.

In accordance with the improved method of this invention, rather thanfixing the mandibular and maxillary bite blocks or trays in a setrelationship with each other by means of quick setting material at thedistal ends of the trays in cooperation with an anterior pin and platestructure as described in our above-mentioned United States patent, aquick setting material in fluid form is pumped directly into a fluidchamber disposed between the opposing bite rims of the bite blocks. Thepressure of this quick setting material while in fluid form ismaintained at a value substantially equal to the physiologic pressurecorresponding to the physiologic pressure characteristic of the patientuntil the quick setting material has hardened. Thus, the angularrelationship of the mandibular and maxillary bite blocks are eilectivelyfixed by hardening of the quick setting material within the entire fluidchamber rather than by hardening of quick setting material at the distalpoints.

There is thus eliminated the need for a modified anterior indexing pinand plate structure in cooperation with specially designed blocks aswell as corrugated support plates at the distal ends of the blocks.Further, the steps of first recording a physiologic pressurecharacteristic of the patient and then re-infiating a flexible tubularchamber to such pressure for subsequently establishing the desiredangular relationships of the blocks are eliminated. As a consequence,the entire method includes less steps and is thus more readily learnedand capable of being more effectively practiced by the dentist.

A better understanding of applicants improved method and apparatus willbe had by now referring to the accompanying drawings, in which:

FIGURE 1 is an exploded plan view of the mandible and maxilla withassociated bite blocks and centric assembly;

FTGURE 2 is a plan view of the mandibular bite block with a flexiblefluid chamber in position; and,

FIGURE 3 is a cross-section of the mandible and maxilla with associatedbite blocks, centric assembly, and inflatable fluid chamber in apatients mouth, the various referred-to portions being shown looking inthe general direction of the arrows 3-3 in the respective diagrams ofFIGURES 1 and 2.

Referring first to FIGURE 1, there is illustrated in plan view themandible 10 and maxilla 11 of a patients month including the generallyarch shaped alveolar ridges 12 and 13 respectively. As shown, suitablemandibular and maxillary bite blocks 14 and 15 are fitted over thealveolar ridges in such a manner as to properly register when thepatients mouth is closed in a normal comfortable position.

A conventional centric assembly is provided for maintaining properanterior-posterior and vertical spacing. This assembly includes amandibular plate 16 irnbedded in a position co-planar with the plane ofthe arch shaped mandibular bite block 14. Plate 16 includes a slideplate 17 provided with a centric pin receiving opening 18 and suitablemeans, such as a screw 15?, for positioning slide plate 17 in a desiredset position with respect to the mandibular plate 16. The maxillary biteblock in turn is provided with a maxillary plate 20 including aprojecting pin 21 receivable within the opening 18 when properanterior-posterior and vertical relationships have been establishedbetween the respective bite blocks.

In accordance with one feature of the present invention, the mandibularplate 16 is modified from the conventional mandibular centric plate bythe provision of three fastening openings 22, 23, and 24 disposedadjacent the inside periphery of the mandibular bite block 14. Theseopenings define the vertices of a triangle. Their purpose will becomeclearer as the description proceeds.

Referring now to FIGURE 2, there is: shown the mandibular bite block 14with its arch shaped upper bite rim substantially covered over itsentire area by a flexible fluid chamber 25. As shown, the chamber 25includes an elongated neck 26 protruding from its front central portionand terminating in a quick connect and disconnect coupling 27. The innerperipheral sides of the arch shaped flexible fluid chamber 25 includeflattened tab portions 22, 23', and 24, provided with openingspositioned to register with the fastening openings 22, 23, and 2 on themandibular centric plate of FEGURE 1. By thisarrangement, suitablesecuring means may be passed through the registered openings forsecuring the inflatable fluid chamber 25 in position. Alternatively oradditionally, further tabs about the outer peripheral side of theflexible fluid chamber 25 as at 28 and 29 may be provided. These in turnare secured to the outer surface of the mandibular bite block by anysuitable pin means.

The relationship of the above-described components in FIGURES l and 2will be better understood by referring to FIGURE 3 showing themandibular and maxillary bite blocks in position over the correspondingalveolar ridges 12 and of a patients mouth. Also shown in cross sectionis the fluid chamber 25 inflated with a quick setting material 39. Theactual bite rims of the mandibular and maxillary bite blocks 14 and 15,themselves, are preferably provided with V-shaped grooves 31 and 32,respectively. When the flexible fluid chamber 25 is infla-ted, itsengaging portions will conform to these V-shaped grooves as shown.

With reference now to all of the'figures, the general method ofestablishing the desired mandibular-maxillary relationships for enablingthe fabrication of properly fitting dentures including the novel stepsof the instant invention will be described. In initially making up themandibular and maxillary bite blocks 14 and 15, snap impressions arefirst made of the patients alveolar ridges in a conventional manner.From these impressions, plaster models of the month are created andcustom-fitted trays formed. These custom-fitted trays in turn areemployed to make master impressions. In making these master impressions,certain of the method steps set forth in our above referred-to US.patent are preferably employed. Thus, a suitable fluid chamber is filledwith air or other fluid for applying a pressure between the opposingtrays themselves to urge the trays and impressiontaki-ng materialtherein into engagement with the alveolar ridges at a pressurecorresponding to the diastolic cardiovascular pressure characteristic ofthe patient.

From these latter impressions, master models are made of hard stone andpositioned on a suitable articulator. From these master models, the biteblocks 14 and 15 are formed, and a primary bite is obtained from thebite blocks by actually fitting the same within the patients mouth.

After the primary bite has been obtained, the bite blocks are returnedto the master models and these master models then re-positioned on thearticulator to insure proper anterior-posterior and verticalrelationships between the bite blocks. l/hen properly adjusted, the pin21 of FIGURE 1 is caused to register in the centric pin receivingopening 18 or" the mandibular slide plate 17 by suitably sliding thisplate to the proper position and tightening the screw 1?. The centricplates and accompanying assembly thus fix the desired anterior-posteriorrelationship as well as the vertical spacing of the bite blocks.

All of the foregoing is normal operating procedure.

In accordance with further conventional or prior art steps in themethod, the bite blocks are then IC-POSlllOIlC-d in the patients mouthand with the patient holding the pin 21 in the pin receiving hole 18,suitable plaster of Paris matrices are applied to the lateral sides ofthe bite blocks While the patient holds the centric. The hardenedplaster of Paris will then fix the bite blocks in a relationship withrespect to each other which will be correct with respect toanterior-posterior and vertical spacing. However, there is no assuranceof correct lateral or anteriorposterior ang lar balance or relationship.

The above will become clearer by reference to applicants FIGURE 3,wherein it will be evident that in the absence of the fluid chamber 25,the patient must eflectively balance the bite blocks about the centricpin 21. Unless this pin is geometrically located at the exact center ofpressure exerted by the patient in bringing his mandible up towards hismaxilla, there is no assurance that the lateral and/ oranterior-posterior relationships of the mandibular and maxillary blockswill be proper. In other words, it is possible that the mandibular biteblock 14- may cant or tilt slightly from a normal axis AA towards aninclined axis A'-A' or about axes extending in anterior-posteriordirections. If such occurs and the plaster of Paris matrices on the twolateral sides of the mouth set, the resulting bite blocks will not beproperly angularly oriented with respect to lateral andanterior-posterior balance although the bite blocks will be properlyoriented with respect to those anterior-posterior and vertical positionsfixed by the centric assembly.

. The resulting dentures fabricated from possible incorrectlyestablished angular relationships of the bite blocks can result inunequal pressures on sides of the mouth when the dentures are worn. Theresult is unequal pressure on the alveolar ridges which produce theaforementioned occlusal disharmonies and soreness, as well as pain.Moreover, such unequal pressures can result in the more serious problemof bone dystrophies. Thus, the osseous foundations change and ratherthan adjust to the particular pressure, are often prone to atrophy morethan necessary so that the unequal pressure distribution is shifted fromone side of the mouth to the other. The original dentures are thusrendered completely out of harmony with the patients alveolar ridgesafter a short period of use.

It is believed the foregoing is the primary cause for repeated callsback to a dentists ofiice for refitting of dentures.

The particular problem of angular unbalance which is the basic cause ofthe improperly fitted dentures is overcome, as mentioned by applicantsprior method as set forth in our prior United States patent. That is,the quick setting material at the distal ends of the mandibular andmaxillary bite blocks is only applied and caused to set with thepresence of the inflatable fluid chamber between the bite blocksinflated to the proper pressure to insure balanced or equal pressures onall areas of the mouth.

The same effective results are achieved in accordance with the method ofthe present invention by employing the particular inflatable fluidchamber 25 depicted in FIGURES 2 and 3. Thus, rather than applying quicksetting plaster of Paris or other quick setting material to the distalends of the bite blocks, the fluid chamber 25 itself is inflated withquick setting material 30 in fluid form to a pressure which isabsolutely uniform and equal about the entire engaging areas of theopposed bite block rims. This uniform pressure is carefully controlledto a value at which the centric pin 21 will lightly engage the centricpin receiving opening 18. In effect, the flexible fluid chamber seatsthe pin 18 in the opening and in cooperation with the patient, theseating pressure corresponds to the diastolic cardio-vascular pressurecharacteristic of the patient himself.

The quick setting material 36 itself is of a nature that it will hardenin from 20 to 40 seconds so that exact angular balance is fixed in aperiod of time considerably shorter than is the case when plaster ofParis matrices are employed.

With correct angular balance achieved, the doctor may then remove thebite blocks and replace them on the master stone models. These masterstone models are then re-positioned on the articulator in accordancewith their pro-established relationship. The entire fluid chambertogether with the hardened quick setting material therein is maintainedbetween the bite blocks when the master stone models are repositioned onthe articulator. The V- shaped grooves in the bite rims enable exactre-positioning of the bite blocks and the fluid chamber to correspond totheir positions when in the pat-ients mouth.

The dentures can then be fabricated by conventional subsequentprocessing.

By employing the above described improved method, the fixedrelationships between the mandible and maxilla can be consistentlyrepeated with a degree of accuracy never heretofore achieved by the oldconventional methods of employing plaster of Paris or other quicksetting material at the distal ends of the bite blocks and relying onthe patient to hold a fixed angular balance.

It is evident that the improved method of this invention greatlysimplifies the steps of insuring angular balance of the bite blocks. Theresulting dentures are substantially perfectly adapted to the patientsmouth, particularly with respect to angular balance, and theaforementioned problems of bone dystrophies and unequal pressures areavoided.

It should be understood that the method can also be employed inre-adapting dentures already manufactured by positioning the fluidchamber between the mandibular and maxillary dentures themselves ratherthan the bite blocks.

In the following claims, the phrase physiologic pressure correspondingto the diastolic cardio-vascular pressure characteristic of the patientincludes that pressure which is correlated to the sensory receptor nerveendings of the alveolar ridges of the particular patient, and which iscontrolled by the neuro-muscular system of the patient. This pressure inpractice is always adjusted to take into consideration the condition ofthe supporting surface. The physiologic pressure for the individual isthus es ablished, assuming the necessary control to prevent distortionor displacement and at the same time utilize the maximum pressurenecessary to establish muscular tonus in the seating of the mandible inthe glenoid fossa.

Further, the term bite block is meant to include bite blocks employed inadapting partial or complete dentures and bridges, and re-adapting thepartial or completed dentures themselves respectively. The term biteblocks as used in the method claimed is also meant to include equivalentmembers such as trays or already completed dentures which fit thealveolar ridges to enable the desired mandibular-maxillary angularrelationships to be established.

What is claimed is:

1. An improved method of establishing angular man dibular-maxillaryrelationship in cooperation with a cendexing pin in previouslyestablished anterior-posteriorvertical position; positioning fluidreceiving means in collapsed condition over the rim area only of saidmandibular-bite block; pumping a quick setting material in fluid forminto said fluid receiving means to provide a uniform pressure betweenthe opposed bite rims of said bite blocks having a value substantiallyequal to the physiologic pressure corresponding to the diastoliccardio-vascular pressure characteristic of the patient; maintaining saidpressure until said quick setting material has hardened whereby saidhardened material will together with said centric pin enablere-establishment of the angular relationship of the mandible andmaxillary in the subsequent fabrication of dentures; and thereaftertransferring the assembly of bite blocks and fluid receiving means withthe hardened material therein to an articulator for further processing.

2. An improved apparatus for establishing angular mandibular-maxillaryrelationships for adapting dentures comprising, in combination: archshaped mandibular and maxillary bite blocks adapted to fit over thecorresponding alveolar ridges of a patient, said bite blocks havingopposed V-shaped grooves in their rims; a flexible fluid chamber ofgenerally arch shaped configuration corresponding to the arch shape ofthe bite rim of said mandibular bite block disposed between said biteblocks in alignment with said V-shaped grooves; means forming a part ofsaid fluid chamber securing said chamber over substantially the entirearea of said mandibular bite rim; a quick setting material in a hardenedstate located in said fluid chamber and forcing said fluid chamber intosaid opposing V-shaped grooves to apply a uniform pressure between theopposing rims of said bite blocks; and means for introducing said quicksetting material in fluid state into said fluid chamber; said hardenedmaterial providing means for subsequently reestablishing the angularrelationship of said mandibular and maxillary bite blocks to enablesubsequent fabrication of said dentures.

3. An apparatus according to claim 2, including a centric assemblysecured to said bite blocks, said centric assembly including amandibular centric plate lying in the plane of the arch of saidmandibular bite block and secured thereto, said plate including anauxiliary slide plate having a centric pin receiving openings; means foradjusting the position of said slide plate with respect to saidmandibular plate and for securing said slide plate to said mandibularplate in a set position; and a maxillary centric plate secured to saidmaxillary bite block and including a centric pin extending substantiallynormally to said mandibular centric plate and received in said centricpin receiving opening when the anterior-posterior and verticalrelationships of said bite blocks have been established, whereby saiduniform pressure may be determined by that pressure exerted by saidpatient through the medium of said bite blocks to said fluid chamberjust sufficient to effect contact of said centric pin with the bottom ofsaid centric pin receiving opening, said pressure being substantiallyequal to the physiologic pressure corresponding to the diastoliccardio-vascular pressure characteristic of said patient.

References Cited in the file of this patent UNITED STATES PATENTS2,562,106 Leathers July 24, 1951 2,773,308 Van Court et a1 Dec. 11, 19522,937,443 Skinner May 24, 1960

1. AN IMPROVED METHOD OF ESTABLISHING ANGULAR MANDIBULAR-MAXILLARYRELATIONSHIP IN COOPERATION WITH A CENTRIC ANTERIOR-POSTERIOR-VERTICALINDEXING PIN, COMPRISING THE STEPS OF: POSITIONING MANDIBULAR ANDMAXILLARY BITE BLOCKS WITH A CENTRIC ASSEMBLY SECURED THERETO OVER THECORRESPONDING ALVEOLAR RIDGES OF A PATIENT WITH SAID INDEXING PIN INPREVIOUSLY ESTABLISHED ANTERIOR-POSTERIORVERTICAL POSITION; POSITIONINGFLUID RECEIVING MEANS IN COLLAPSED CONDITION OVER THE RIM AREA ONLY OFSAID MANDIBULAR BITE BLOCK; PUMPING A QUICK SETTING MATERIAL IN FLUIDFORM INTO SAID FLUID RECEIVING MEANS TO PROVIDE A UNIFORM PRESSUREBETWEEN THE OPPOSED BITE RIMS OF SAID BITE BLOCKS HAVING A VALUESUBSTANTIALLY EQUAL TO THE PHYSIOLOGIC PRESSURE CORRESPONDING TO THEDIASTOLIC CARDIO-VASCULAR PRESSURE CHARACTERISTIC OF THE PATIENT;MAINTAINING SAID PRESSURE UNTIL SAID QUICK SETTING MATERIAL HAS HARDENEDWHEREBY SAID HARDENED MATERIAL WILL TOGETHER WITH SAID CENTRIC PINENABLE RE-ESTABLISHMENT OF THE ANGULAR RELATIONSHIP OF THE MANDIBLE ANDMAXILLARY IN THE SUBSEQUENT FABRICATION OF DENTURES; AND THEREAFTERTRANSFERRING THE ASSEMBLY OF BITE BLOCKS AND FLUID RECEIVING MEANS WITHTHE HARDENED MATERIAL THEREIN TO AN ARTICULATOR FOR FURTHER PROCESSING.